Low insertion force connector for modular circuit packages

ABSTRACT

Connector for modular circuit packages including several male leads, such as large scale integrated circuit packages. The connector has a housing including a base with a carriage movable in a cavity in the base between outer and inner positions. The carriage is prevented from moving out of the cavity beyond its outer position so that the parts are maintained in assembled relation for convenient use. The modular circuit package is placed on a support surface on the carriage, and its leads enter recesses in the housing with no insertion force. A number of terminals are carried by the housing, and each includes a spring contact normally positioned to permit free entry of a lead into its recess. After the modular circuit package is placed on the carriage with its leads in the recesses, the package and the carriage are pressed to move the carriage from the outer to the inner position and cam means on the carriage engage the terminals to force the spring contacts against the package leads within the lead receiving recesses. Resilient tabs releasably latch the carriage in its inner position while permitting convenient release of the carriage for replacing the package.

United States Patent t Tom kiewicz [75] lnventor: Thaddeus K.Tomkiewicz,

Bolingbrook, 111.

[73] Assignee: Molex Incorporated, Lisle, I11.

{22] Filed: Sept. 13, 1973 [21] Appl. No.: 396,822

[52] US. Cl 339/75 M; 339/17 C; 339/217 8 [51] Int. Cl. H01!- 13/54 [58]Field of Search 339/75, 174, 17 C, 17 CF, 339/217 S [5 6] ReferencesCited UNITED STATES PATENTS 2,857,577 10/1958 Vanderpool 339/75 MP3,474,387 10/1969 Krum et a1. 339/75 MP 3,648,221 3/1972 Tillman et a1339/74 R 3,750,085 7/1973 Cooper 339/75 M Primary Examiner-MarionParsons, Jr. Assistant Examiner-Robert A. Hafer Attorney, Agent, orFirm-Mason, Kolehmainen, Rathburn & Wyss [451 May 13, 1975 {57] ABSTRACTConnector for modular circuit packages including several male leads,such as large scale integrated circuit packages. The connector has ahousing including a base with a carriage movable in a cavity in the basebetween outer and inner positions. The carriage is prevented from movingout of the cavity beyond its outer position so that the parts aremaintained in assembled relation for convenient use. The modular circuitpackage is placed on a support surface on the carriage, and its leadsenter recesses in the housing with no insertion force. A number ofterminals are carried by the housing, and each includes a spring contactnormally positioned to permit free entry of a lead into its recess.After the modular circuit package is placed on the carriage with itsleads in the recesses, the package and the carriage are pressed to movethe carriage from the outer to the inner position and cam means on thecarriage engage the terminals to force the spring contacts against thepackage leads within the lead receiving recesses. Resilient tabsreleasably latch the carriage in its inner position while permittingconvenient release of the carriage for replacing the package.

13 Claims, 8 Drawing Figures j 1 48 22 I6 75 -i-3 LOW INSER'IION FORCECONNECTOR FOR MODULAR CIRCUIT PACKAGES The present invention relates toconnectors for modular circuit packages, and more particularly toconnectors of the type referred to as low or zero insertion forcesockets.

The term modular circuit package" as used herein is intended toencompass devices such as large scale integrated circuit packages (knownas LSl's), dual-in-line packages and other packages or devices havingplural male leads.

The traditional method of mounting circuit components to printed circuitboards is to solder the extending leads to conductive areas of theboard. Disadvantages of this method are the expense of carrying out thesoldering operation and the difficulty in replacing previously solderedcomponents. These difficulties become quite serious with sophisticatedmodern modular circuit packages such as dual-in-line packages having,for example, eight or fourteen leads, and LSls having, for example,forty leads.

In order to overcome the problems encountered with soldering componentsto external circuitry, various types of socket connectors having beendeveloped. Examples of such connectors utilized for transistor devicesand dual-in-line packages respectively are disclosed in U.S. Pats. Nos.3,5 l6,044 Barnes et al. and 3,673,543 Garner. Although the connectorsillustrated in these patents do overcome the problem of difficulty inreplacement of circuit components, nevertheless they are subject toother disadvantages. A primary difficulty is that in order to mount thecircuit component in the socket, it is necessary to apply a force to themale leads.

Devices such as LSIs not only include many leads, but also the leads arequite fragile and delicate. In the use of a connector of the typerequiring insertion forces to be applied to leads, the total forcerequired is substantial when many leads are involved. In addition, dueto the fragile nature of the leads, the leads may be unable toaccommodate insertion forces without bending or otherwise becomingdamaged.

Devices known in the art as zero or low insertion force sockets havebeen developed for the releasable mounting of modular circuit packages.An example of such a device is disclosed in U.S. Pat. No. 3,683,317Walkup. Known structures of this character are subject to disadvantagesincluding the lack of support for the modular circuit package, the forcerequired to bring about connection to the package leads after mountingof the package, difficulty in mounting of a package due to the fact thatthe connector includes separate and unattached housing parts, anddifficulty in releasing the package for replacement after initialmounting in the connector.

Among the important objects of the present invention are to provide animproved low insertion force connector for modular circuit packageswhich is simple to use, reliable in operation, and inexpensive tomanufacture, and to overcome the disadvantages encountered in knownarrangements. Further objects are to provide a connector includingrelatively movable housing parts that are maintained in assembledrelationship prior to use; to provide a connector wherein a packagemounted on the connector is adequately supported; to provide a connectorhaving novel structure for establishing electrical connections toinserted package leads;

and to provide a connector wherein release of a package after initialmounting can readily be effected.

Briefly, in accordance with the above and other objects and advantagesof the present invention, there is provided a connector for a modularcircuit package of the type including several male leads. The connectorincludes a housing having two parts a base with a cavity definedtherein, and a carriage mounted in the cavity for movement between outerand inner positions. A retaining structure maintains the carriage andthe base in assembled condition and prevents the carriage from movingout of the cavity beyond its outer position. The carriage includes anexternally facing support surface against which a modular circuitpackage is supported. Recesses are provided in the housing for receivingthe leads of the package when the package is placed on the supportsurface. Several terminals are mounted in the housing, and each includesa spring contact normally positioned adjacent the lead receiving recessso that an unobstructed path is provided for free entry of the leads.When the carriage is moved from its outer to its inner position, camsurfaces on the carriage engage the terminals to force the springcontacts into firm engagement with the leads of the package. Resilientlatching tabs on the base engage the carriage in the inner position inorder to hold the carriage in place and to permit convenient release andreplacement of the package.

The invention and its objects and advantages may be more fullyunderstood from consideration of the following detailed description ofthe embodiment of the invention illustrated in the accompanyingdrawings, wherein:

FIG. 1 is a sectional view of a connector constructed in accordance withthe principles of the invention, taken along the line 1-1 of FIG. 3, andillustrating the connector mounted on a printed circuit board and duringmounting of a modular circuit package;

FIG. 2 is a view similar to FIG. I illustrating the connector aftermounting of the modular circuit package;

FIG. 3 is a sectional view of the connector of FIG. 1 taken along theline 3-3 of FIG. I, with certain structure omitted for clarity;

FIG. 4 is a fragmentary view similar to part of FIG. 3 illustrating theconnector after mounting of the modular circuit package;

FIG. 5 is a fragmentary top view of the connector of FIG. 1;

FIG. 6 is a fragmentary bottom view of the connector of FIG. 1;

FIG. 7 is an enlarged elevational side view of a terminal of theconnector of FIG. I; and

FIG. 8 is another side view of the terminal of FIG. 7.

With reference now to the drawings, there is illustrated a connectordesignated as a whole by the reference numeral 10 and constructed inaccordance with the principles of the present invention. The connector10 serves to establish releasable electrical connections with and tosupport a modular circuit package 12 and to electrically interconnectthe package 12 with conductive regions 14 of a printed circuit board 16.The package 12 in the illustrated arrangement comprises a large scaleintegrated circuit package, or LSI, having an array of forty male leads18 in a standard double row configuration. The principles of theinvention may be applied to connectors for many types of modular circuitpackages including dual-in-line packages, semiconductor components, andothers. Similarly, although the connector 10 of the present invention isdesigned for mounting upon and connection to conductive areas 14 of theprinted circuit board 16, connectors of the present invention may beadapted for interconnection with external circuitry of many types.

In general, the connector l includes a housing generally designated as20 comprised of a base member 22 having a cavity 24 therein and acarriage 26 supported for movement in the cavity 24. In FIGS. 1, 3, and6 the carriage 26 is illustrated in an outer position relative to thebase member, and a retaining structure gen erally designated as 28(FIGS. 3 and 4) is provided to prevent withdrawal of the carriage 26from the cavity 24 beyond the outer position. In FIGS. 2 and 4 the carriage is illustrated in an inner position, and a latching structuregenerally designated as 30 (FIGS. 3 and 4) is provided to hold thecarriage 26 in place with respect to the base 22 when it is pushed toits inner position.

In order to support the modular circuit package 12 in position on theconnector 10, the carriage 26 is provided with a support surface 32facing outwardly of the connector and against which the base of thepackage 12 may be placed. Base 22 is provided with a number of leadreceiving recesses 34 flanking the mouth of cavity 24 and correspondingto the array of leads 14 of the modular circuit package 12. When thepackage 12 is placed upon the support surface 32 as illustrated in FIG.I, the leads 14 enter the recesses 34.

Electrical connection is made to the leads 18 by means of a plurality ofterminals 36 corresponding in number to the leads l8 and recesses 34.Each terminal 36 includes a spring contact portion 38 which, in thenormal or relaxed condition of the terminal 36, is dis-- posed for freeand unobstructed entry of the corresponding lead 18 into thecorresponding recess 34. When the modular circuit package 12 togetherwith the carriage 26 is pushed from the outer position of FIG. 1 to theinner position of FIG. 2, cam surfaces 40 of the carriage 26 engage theterminals 36 to force the spring contacts 38 firmly into engagement withthe leads 18 thereby to establish reliable electrical connection to theleads and to hold the package 12 firmly in position.

Proceeding now to a more detailed description of the illustratedembodiment of the invention. the base 22 is generally rectangular orbox'like in shape, and has a configuration complementary to that of themodular circuit package 12. The base 22 includes a peripheral generallycontinuous outer wall made up of opposed side walls 42 and opposed endwalls 44. As best seen in FIG. 5, the cavity 24 for receiving thecarriage 26 is defined centrally of the walls 42 and 44. Side walls 42are spanned at spaced locations by a series of struts or ribs 46, andthe uppermost edges of the struts 46 define the innermost extent ofcavity 24. The bottom of the base 22 is spaced slightly from the printedcircuit board 16 by means ofa number of protrusions 48 in order topermit the flow of heat and/or gasses which may occur during mounting ofthe base 22 to the board 16 by sol dering of terminals 36, and also toprovide for ventilation of the modular circuit package 12.

Carriage 26 is complementary in shape to and somewhat smaller than base22, and fits snugly into cavity 24. The carriage 26 includes spaced endwalls 50 and side walls 52. In order to provide for rigidity of the carriage 26, and to permit ventilation of the package 12, the side walls 52are interconnected at spaced points by a series of struts or ribs 54.The outermost portions of the side walls 52 form the support surface 32for the modular circuit package 12, and the end walls 50 are extendedoutwardly to provide protective walls or guards 56 flanking the ends ofthe package 12. Cam surfaces are formed on the sides of walls 52.

As indicated above, the carriage 26 may be moved inwardly and outwardlyof the base 22 between the outer position illustrated in FIGS. 1, 3, 5and 6 and the inner position illustrated in FIGS. 2 and 4. In theillustrated arrangement, the base 22 and carriage 26 are fabricated asseparate parts and thus are not integrally joined with one another.After fabrication, the carriage 26 is aligned over cavity 24 of base 22and pushed inwardly. The carriage is guided to the proper position andis thereafter guided in movement between the inner and outer positionsby means of a pair of guide projections 58 associated with the end wallsof the carriage 26 movable in guide slots 60 formed in the end walls 44of the base 22.

When the carriage 26 is initially assembled with the base 22, theretaining structure 28 permits assembly of the parts and thereaftermaintains the parts in assembled arrangement for convenience in use ofthe connector 10. As best seen in FIGS. 3 and 4, the retaining structure28 includes a pair of generally hook-shaped fingers 62 formed asresilient integral extensions of a pair of the struts 46 of base 22.Fingers 62 are engageable with shoulders 64 formed on a pair of struts54 of the carriage 26. When the carriage is initially guided into cavity24, cam surfaces 66 on the fingers 62 cause the lingers to be deflectedaround the corresponding struts 54, and as the carriage 26 reaches theouter posi tion, the fingers resiliently snap inwardly to overlie theshoulders 64 and prevent subsequent movement of the carriage 26 from thecavity 24.

It is contemplated that the assembled connector 10 may be left in thecondition illustrated in FIG. 1 with the carriage 26 in its outerposition until the connector 10 is used to mount a modular circuitpackage. When a package 12 is mounted, the carriage 26 is moved to itsinner position, and the latching structure 30 the reafter holds thecarriage in the inner position. Latching structure 30 comprises a pairof resilient latching tabs 68 formed integrally with the end walls 44 ofthe base 22. Each tab 68 is somewhat hook shaped in configuration andincludes an end or nose surface 70 which rides over the outer surface ofthe end wall 50 of the carriage 26. As best seen in FIG. 3, the tabs 68are bent resiliently outwardly by contact of the end surfaces 70 withthe walls 50 and this results in a frictional detaining force beingapplied to the carriage 26 so that it is frictionally detained in itsouter position pending use.

When the carriage 26 is moved from its outer position to its innerposition by pushing against the frictional force applied by the tabs 68to the walls 50, inad vertent withdrawal of the carriage is prevented byen gagement of the tabs 68 with locking shoulders 72 provided on thewalls 50. However, it should be noted that the extremities of the tabs68 are smooth and rounded so that they may easily be grasped anddisplaced outwardly by hand in order to provide for release of thecarriage 26 from the inner position. In addition, release is facilitatedby the fact that the tabs 68 are readily ac cessible at the outer endsof the base 22.

One terminal 36 of the connector 10 is illustrated in detail in FIGS. 7and 8. Each terminal includes a getterally straight shank portion 74terminating in a pin contact portion 76 extending from base 22 ofconnector I0. Pin contact 76 can be connected to external circuitry suchas conductive areas 14 of the printed circuit board 16 by anyconventional soldering process. Near the opposite end of the shankportion 74, the terminal 36 is provided with a widened region 78 fromthe central area of which there is outwardly struck a resilient lockingtang 80.

Spring contact portion 38 of the terminal 36 is formed by a generallyU-shaped segment of the terminal. The spring contact 38 is displaced tothe side of the plane of the shank portion 74 by means of a transverselyextending segment 82. The extremity of spring contact 38 is providedwith an enlarged or widened head portion 84.

Conveniently, in assembly of the connector the terminals 36 are simplyinserted into the base 22 and are retained in place by means of thelocking tangs 80 and transverse segments 82. More specifically, and ascan best be seen in FIG. 5, each lead receiving recess 34 is generallysquare in cross section and extends from the top wall of the base 22.The recesses 34 correspond in number and position to the leads 18 of themodular circuit package 12, and are of ample size to permit free andunobstructed entry of the leads into recesses. Each recess 34communicates with the cavity 24 by means of a slot or channel 86 ofnarrower width than the recess 34.

As a terminal 36 is inserted into the base 22, the pin contact portion76 is directed downwardly into the lead receiving recess 34. The widenedarea 78 maintains the terminal in the desired position within recess 34as downward movement of the terminal continues. The leading end or pincontact portion 76 enters a channel 88 extending downwardly from therecess 34 and strikes a sloped guiding surface 90 to guide the pincontact 76 downwardly out of the base 22. As the locking tang 80 reachesthe bottom of the lead receiving recess 34, it is resiliently compressedinwardly toward the shank portion 74, and when the terminal 36 is fullyinserted, the tang 80 snaps outwardly to engage a shoulder 92 andprevent inadvertent withdrawal of the terminal from the base 22. Accessopenings 94 are provided so that the tangs 80 may be depressed forwithdrawal of terminals 36 if desired. Upon full insertion of eachterminal 36, the transverse segment 82 abuts against the bottom of thecorresponding slot 86 in order to prevent overinsertion of the terminal.

Because the leads 18 of the modular circuit package 12 may be large innumber and may be quite fragile and delicate due to their small size, itis desired that the force applied to the leads in mounting of thepackage 12 be as little as possible. For this reason, the terminals 36are arranged so that movement of the leads 18 into the recesses 34 iscompletely unobstructed. As can best be seen in FIG. I, in the relaxedposition of the terminals 36 the spring contacts 38 lie for the mostpart in the slots 86 and in the cavity 24. Only the widened head portion84 of the spring contacts 38 are retained within the recesses 34 so thatthe leads 18 are easily inserted between the spring contacts 38 andwalls 96 of the recesses 34 opposite the contacts 38.

After placing the modular circuit package 12 on the ity 24 from theouter position to the inner position. The side walls 52 of the carriage26 are provided with the cam surfaces 40 of sufficient extent to overlieall of the terminals 36. During inward movement of the carriage, the camsurfaces 40 engage the portions of the spring contacts 38 lying withinthe cavity 24 and force the spring contacts 38 into the recesses 34.Consequently, as best seen in FIG. 2, the spring contacts 38 are pushedtransversely against the leads I8 and firmly and resiliently capture theleads 18 between the spring contacts 38 and walls 96. Excessive force isnot required due to the mechanical advantage afforded by the camsurfaces 40 acting against spring contacts 38. A reliable electricalconnection is made to each lead [8 by its corresponding terminal 36 andby firm engagement of the leads [8 the modular circuit package [2 isheld in position supported against the support surface 32 of thecarriage 26.

Subsequent to initial mounting of the modular circuit package 12 in theconnector 10, replacement of the package 12 may be required. In thisevent, it is possible to release the carriage 26 from its inner positionsimply by outward movement of the latching tabs 68. Due to the resilientnature of the spring contacts 38 and their engagement with the camsurfaces 40, the carriage 26 together with the package 12 snaps or popsoutwardly from the inner position of FIG. 2 to the outer position ofFIG. 1 upon release of the latching structure 30. At this point themodular circuit package 12 can easily be lifted from the connector 10and replaced with a new package 12 to be mounted.

Although the invention has been described with reference to details ofthe illustrated embodiment, such details are not intended to limit theinvention as defined in the following claims.

What is claimed and desired to be secured by Letters Patent of theUnited States is:

l. A connector for a modular circuit package including plural maleleads, said connector comprising:

a housing including a base and having base wall means defining a cavitytherein and a carriage mounted in said cavity for movement between outerand inner positions;

retaining means on said base and carriage for preventing movement ofsaid carriage from said cavity beyond said outer position;

an externally directed support surface on said carriage adapted toreceive the circuit package;

recess means in said base wall means housing defining a plurality oflead receiving paths for receiving the leads of a circuit packagedisposed on said support surface;

a plurality of terminals mounted in said housing, each including aspring contact normally positioned partly within said cavity adjacentone said lead receiving path and permitting unobstructed entry of a leadinto said path; and

means on said carriage slidably engaging said terminals upon movement ofthe carriage from the outer position to the inner position and cammingsaid spring contacts transversely into said lead receiving paths andagainst the inserted leads.

2. The connector of claim 1, further comprising releasable latch meanson said base and carriage for retaining said carriage in said innerposition.

3. The connector of claim 2, said carriage including carriage wall meanstelescoped within said base wall means, said releasable latch meansincluding resilient tab means formed integrally with one said wall meansand latch shoulder means on the other said wall meansv 4. The connectorof claim 3, two sets of said tab and shoulder means disposed at oppositepoints on the outer periphery of said housing.

5. The connector of claim 1, said base wall means including opposed sidewalls and opposed end walls surrounding said cavity, said recess mcanscomprising two rows of recesses, one row in each of said side wallsflanking said cavity.

6. The connector of claim 5, a slot extending between each said recessand said cavity, each spring contact being disposed partly in saidcavity and partly in said slot in the outer position of said carriage,and said camming means including cam surfaces on the carriage engagingeach said spring contact in said cavity to move said contacts throughsaid slots toward said recesses upon movement of said carriage to itsinner position.

7. The connector of claim 6, each said spring contact including anenlarged portion received in said recess for retaining said enlargedportion outside of said slot.

8. The connector of claim 5, channel means extending from each saidrecess to the exterior of said base, and each terminal including anadditional contact structure extending into said channel means 9. Theconnector of claim 8, said additional contact structure comprising a pincontact.

10. The connector of claim 8, resilient tang means on said terminals andshoulder means in said base for retaining said terminals in said base.

11. The connector of claim 1, said carriage including guard wallsflanking said support surface and extending outwardly from the supportsurface a distance larger than the height of the package.

12. A connector for a modular circuit package including plural maleleads. said connector comprising;

a housing including a base having a cavity defined in part between apair of opposed side walls;

a carriage mounted in said cavity for movement between outer and innerpositions;

an externally directed support surface on said carriage adapted toreceive the circuit package;

recess means in said housing defining a plurality of lead receivingpaths for receiving the leads of a circuit package disposed on saidsupport surface said recess means comprising two rows of recesses, onerow in each of said opposed side walls flanking said cavity. each recessincluding a portion open to said cavity;

a terminal mounted in said housing adjacent each recess, each includinga first terminal portion held by said housing and an otherwiseunsupported spring contact extending from said first portion andnormally positioned adjacent one said lead receiving path and permittingunobstructed entry of a lead into said path, each spring contact in itsnormal position including a first segment disposed in said recess and asecond segment extending into said cavity from the corresponding one ofsaid side wall; and

a pair of opposed cam surfaces on said carriage engageable with saidsecond segments of said terminals upon movement of the carriage from theouter position to the inner position for forcing said spring contactstransversely outwardly into said lead receiving paths and against theinserted leads.

13. A connector as claimed in claim 12 each said portions of saidrecesses open to said cavity comprising a slot of reduced width, saidfirst segment of said spring contact of each terminal including a headportion wider than said slot.

1. A connector for a modular circuit package including plural maleleads, said connector comprising: a housing including a base and havingbase wall means defining a cavity therein and a carriage mounted in saidcavity for movement between outer and inner positions; retaining meanson said base and carriage for preventing movement of said carriage fromsaid cavity beyond said outer position; an externally directed supportsurface on said carriage adapted to receive the circuit package; recessmeans in said base wall means housing defining a plurality of leadreceiving paths for receiving the leads of a circuit package disposed onsaid support surface; a plurality of terminals mounted in said housing,each including a spring contact normally positioned partly within saidcavity adjacent one said lead receiving path and permitting unobstructedentry of a lead into said path; and means on said carriage slidablyengaging said terminals upon movement of the carriage from the outerposition to the inner position and camming said spring contactstransversely into said lead receiving paths and against the insertedleads.
 2. The connector of claim 1, further comprising releasable latchmeans on said base and carriage for retaining said carriage in saidinner position.
 3. The connector of claim 2, said carriage includingcarriage wall means telescoped within said base wall means, saidreleasable latch means including resilient tab means formed integrallywith one said wall means and latch shoulder means on the other said wallmeans.
 4. The connector of claim 3, two sets of said tab and shouldermeans disposed at opposite points on the outer periphery of saidhousing.
 5. The connector of claim 1, said base wall means includingopposed side walls and opposed end walls surrounding said cavity, saidrecess means comprising two rows of recesses, one row in each of saidside walls flanking said cavity.
 6. The connector of claim 5, a slotextending between each said recess and said cavity, each spring contactbeing disposed partly in said cavity and partly in said slot in theouter position of said carriage, and said camming means including camsurfaces on the carriage engaging each said spring contact in saidcavity to move said contacts through said slots toward said recessesupon movement of said carriage to its inner position.
 7. The connectorof claim 6, each said spring contact including an enlarged portionreceived in said recess for retaining said enlarged portion outside ofsaid slot.
 8. The connector of claim 5, channel means extending fromeach said recess to the exterior of said base, and each terminalincluding an additional contact structure extending into said channelmeans.
 9. The connector of claim 8, said additional contact structurecomprising a pin contact.
 10. The connector of claim 8, resilient tangmeans on said terminals and shoulder means in said base for retainingsaid terminals in said base.
 11. The connector of claim 1, said carriageincluding guard walls flanking said support surface and extendingoutwardly from the support surface a distance larger than the height ofthe package.
 12. A connector for a modular circuit package includingplural male leads, said connector comprising; a housing including a basehaving a cavity defined in part between a pair of opposed side walls; acarriage mounted in said cavity for movement between outer and innerpositions; an externally directed support surface on said carriageadapted to receive the circuit package; recess means in said housingdefining a plurality of lead receiving paths for receiving the leads ofa circuit package disposed on said support surface, said recess meanscomprising two rows of recesses, one row in each of said opposed sidewalls flanking said cavity, each recess including a portion open to saidcavity; a terminal mounted in said housing adjacent each recess, eachincluding a first terminal portion held by said housing and an otherwiseunsupported spring contact extending from said first portion andnormally positioned adjacent one said lead receiving path and permittingunobstructed entry of a lead into said path, each spring contact in itsnormal position including a first segment disposed in said recess and asecond segment extending into said cavity from the corresponding one ofsaid side wall; and a pair of opposed cam surfaces on said carriageengageable with said second segments of said terminals upon movement ofthe carriage from the outer position to the inner position for forcingsaid spring contacts transversely outwardly into said lead receivingpaths and against the inserted leads.
 13. A connector as claimed inclaim 12 each said portions of said recesses open to said cavitycomprising a slot of reduced width, said first segment of said springcontact of each terminal including a head portion wider than said slot.